Protocol Adapter for Passing Diagnostic Messages Between a Host Computer and Vehicle Networks Operating in J1939 or J1708 Protocol

1. A protocol adapter for transferring diagnostic messages between a vehicle network in a vehicle and an external host computer, said adapter comprising: a plurality of transceiver circuits for providing an interface between the vehicle network and the host computer when the vehicle network is operating in one of a plurality of protocols; wherein the adapter automatically switches to one or more of the plurality of protocols the host computer is using; and further comprising a central processing unit (CPU), said CPU controlling the operation of the plurality of transceiver circuits to automatically switch between the plurality of transceiver circuits, depending on which of the plurality of protocols the host computer is using.

2. The protocol adapter according to claim 1 one of said plurality of transceiver circuits further comprising an RS-232 transceiver, said RS-232 transceiver circuit providing an interface to an RS-232 port on the host computer.

3. The protocol adapter according to claim 1 , further comprising a device decoder, said device decoder decoding input signals sent to the CPU.

4. The protocol adapter according to claim 1 , further comprising a static random access memory (RAM) circuit, said RAM circuit including a RAM that provides temporary data storage and is connected to the CPU through data and address channels.

5. The protocol adapter according to claim 4 wherein the RAM circuit further provides redirection of mailbox data, storage for oversized messages and the concatenation of small messages.

6. The protocol adapter according to claim 1 , further comprising a flash memory module, said flash memory module providing permanent storage of application data and loader application information.

7. The protocol adapter according to claim 1 , further comprising a universal asynchronous receive and transmit (UART) circuit, said UART circuit providing communication of asynchronous data to and from the host computer.

8. The protocol adapter according to claim 1 , further comprising a CPU I/O interface circuit, said CPU I/O interface circuit providing an interface between the CPU and the transceiver circuits.

9. A protocol adapter for transferring diagnostic messages between a vehicle network in a vehicle and an external host computer, said adapter comprising: a plurality of transceiver circuits for providing an interface between the vehicle network and the host computer when the vehicle network is operating in one of a plurality of protocols; a central processing unit (CPU), said CPU controlling the operation of the plurality of transceiver circuits to automatically switch between the plurality of transceiver circuits, depending on which of the plurality of protocols the host computer is using; and a voltage translator for translating the voltage of one or more of said plurality of protocols, said voltage translator being part of one of said plurality of transceiver circuits.

10. The protocol adapter according to claim 9 , one of said plurality of transceiver circuits further comprising an RS-232 transceiver, said RS-232 transceiver circuit providing an interface to an RS-232 port on the host computer.

11. The protocol adapter according to claim 9 , further comprising a static random access memory (RAM) circuit, said RAM circuit including a RAM that provides temporary data storage and is connected to said CPU through data and address channels.

12. The protocol adapter according to claim 11 wherein the RAM circuit further provides redirection of mailbox data, storage for oversized messages and the concatenation of small messages.

13. The protocol adapter according to claim 9 further comprising a flash memory module, said flash memory module providing permanent storage of application data and loader application information.

14. The protocol adapter according to claim 9 further comprising a universal asynchronous receive and transmit (UART) circuit, said UART circuit providing communication of asynchronous data to and from the host computer.

15. The protocol adapter according to claim 9 , further comprising a CPU I/O interface circuit, said CPU I/O interface circuit providing an interface between said CPU and the transceiver circuits.

16. The protocol adapter according to claim 9 , one of said plurality of transceiver circuits further comprising a J1708 transceiver circuit, said J1708 transceiver circuit providing an interface between the vehicle network and the host computer when the vehicle network is operating in a J1708 protocol and the protocol adapter is operating in a pass-through mode, said J1708 transceiver circuit including the voltage translator for translating the voltage of the J1708 protocol signals.